Paving machines are used to apply, spread and compact paving material relatively evenly over a desired surface. These machines are regularly used in the construction of roads, parking lots and other areas where a smooth durable surface is required for cars, trucks and other vehicles to travel. An asphalt paving machine generally includes a hopper for receiving asphalt material from a truck and a conveyor system for transferring the asphalt rearwardly from the hopper for discharge onto a roadbed. Screw augers may be used to spread the asphalt transversely across the roadbed in front of a screed plate. The screed plate smoothes and somewhat compacts the asphalt material and ideally leaves a roadbed of uniform depth and smoothness.
Although the screed plate compacts the asphalt material to some extent, it may be desirable to pre-compact the asphalt material prior to its engagement by the screed plate. A tamper mechanism may be positioned between the screw auger and the screed plate to perform such pre-compacting operation. Tamper mechanisms often includes a tamper bar, located in front of the screed plate relative to the direction of travel of the paving machine and extending transversely to the direction of travel. The tamper bar moves up and down, striking the asphalt material on each downward stroke to compact the asphalt material.
In some instances, it may be desirable to adjust the length of the stroke or amplitude of the movement of the tamper bar. For example, it may be desirable to adjust the length of the stroke depending on the desired thickness of the paved surface. The characteristics of the paving material as well as the speed of the paving machine may also contribute to a desired stroke length. However, existing tamper mechanisms generally require a time consuming process to adjust the tamper bar stroke. As a result, operators of paving machines often do not adjust the length of the stroke due to time constraints.
U.S. Patent Publication No. 2011/0123270 discloses a tamper mechanism that includes a tamper bar with an adjustable stroke length. An eccentric shaft is driven by a drive motor to move the tamper bar up and down. An eccentric bushing is provided that engages an eccentric section of the eccentric shaft. The length of the stroke of the tamper bar may be adjusted by loosening or removing hardware and then rotating the eccentric bushing relative to the eccentric section of the shaft. Once the eccentric bushing is positioned in the desired position relative to the eccentric section of the shaft, the bushing and shaft are fixed relative to each other by tightening or reapplying the mounting hardware.
The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims.